I have been playing around with http://wolframalpha.com lately and it has a lot of power behind it. I mostly use it for doing math stuff when I don't have a calculator in front of me and it can even do some stuff I cant do on my ti-89 like Laplace transforms. When it returns a result it often time gives a comparison of other things that have the same unit. As an example, I asked it about 15 gigs and it immediately figured out what I was talking about and told me how big that was in relation to a blueray disk,60%, as well as how long it would download at different speeds. All this information got me thinking about what kind of questions it can answer and what it cant. The questions it cant answer fall into 3 main categories and while I could never list all the things it can answer I can easily list what kind of questions I want it to answer.

"average size of an iphone app in the apple app store" - while this query would take a lot of work to acquire the requisite data I think it could be answered one day by a computer but it is mostly a issue with data mining apples app store which they probably wouldn't like. This is just a data issue and it could be worked out in time since right now it can answer similar questions like "average income of a person"

"meaning of life" - this is an obvious one that cant be answered, it falls into the category of being incalculable. When a question is asked that there is no data to the next best thing that can be done is a interpretation which is exactly what Wolframalpha does. In this case its knows the answer to the ultimate question of life the universe and everything but not the question itself so it displays that. 42.

"what is the best way to ..." - Wolfram was designed to answer questions with facts and not opinions so this type of question should never really be handled

Wolframalpha is very cool right now and I hope that they can expand the focus of their domain as it is mostly geared to math type questions at the moment. This is understandable since their expertise has been math software and since that is where knowledge is the most quantitative. While this article was mostly to cover what it cant do, you should check out the examples page on the Wolframalpha site to see what it excels at and hopefully by the time you read this article it will be out of date.